Angiosperm Life Cycle

Angiosperm Life Cycle

By: Ankit Datta

Summary of video:
This video summarizes the reproductive cycle of angiosperms. Angiosperms are flowering plants that have a specialized organ called an ovary to produce seeds and protect it while it is still forming. This video discusses: the parts of the flower, pollen development, egg development, pollination, double fertilization, seed development and fruit development. First, the parts of the flower. A flower has sepals which cover growing buds, petals, filaments ( the long and skinny, tube-looking things) and anthers (yellow buds on the filament) which together, combine to make the male part of the flower. This is also the structure in which pollen is produced. The female part of the flower is made up of: the stigma (the opening of the vase-looking structure), the style (the long neck), and the ovary (the bottom swollen part). These three together form the carpel which is the female part. Next, the video addresses pollen development. Pollen develops inside the stamen where a diploid microspore mother cell undergoes meiosis and then mitosis to become pollen grains which are male gametophytes. Next comes egg development. Ovules inside the ovary produce eggs. Inside, a diploid megaspore mother cell undergoes meiosis to form megaspores. Only 1 out of 4 survives and then goes on through 3 rounds of mitosis to make an egg and an endosperm. Next is pollination. Wind and pollinators help plants pollinate where a pollen grains lands on the stigma. Next is double fertilization where the pollen grain has two parts: tube and generative. The tube cell attaches onto the egg cell and the generative cell makes two sperm, one for the egg to produce a zygote and one for the endosperm to make a triploid endosperm. Next is seed development. The ovule slowly over time becomes the seed and everything inside becomes the seed. Finally, there is fruit development. The ovaries swell and the petals fall off and the ovary grows completely to become a fruit.

Relevance to class:

This video discusses angiosperms and its life cycle. In this unit, we discussed plant evolution and how angiosperms were the last to evolve and are the only type of plant that have ovaries and flower in order to attract pollinators. We are also discussing the different parts of a flower and this video adequetly describes each part and its functions.

Video URL: http://www.youtube.com/watch?v=AykzPemLs7Q
Creator: Craig Savage
Date published: April 9, 2012

Enhancing genes to Evolve Quickly

 Summary:
Scientists and researchers in Spain have been working on zebra fish, they have found out that adding a genetic switch called an enhancer will turn up a gene called Hoxd13 at the tips of developing fins. Adding more Hoxd13 produced limbs that had more cartilage and less fin material on the zebra fish. The researchers reported on Dec. 11, that ancestors of four-legged creatures may have acquired these enhancers, which lead them to limb development.

Relevan
We recently learned how evolution occurs and how it takes generations to do. With modern technology such as the one in article, researchers are now able to speed up the process of it to study. This method can speed up the evolution from sea creatures to four legged animals in just a matter of days or weeks. The article also shows how the process of evolution is just the changing of a gene. Like in the article, the switch from fins to limbs is just a adding more of a gene.

Article Info:
Url: http://www.sciencenews.org/view/generic/id/346972/description/News_in_brief_Fins_to_limbs_with_flip_of_genetic_switch
Author: Tina Hesman Saey
Date of Publication: December 12, 2012

Richard Tang

Plants Use Caffeine to Lure Bees, Scientists Find

Summary:

A new study shows that the naturally caffeine-laced nectar of some plants encourages bees to return to those flowers. Plants want pollinators to stay "faithful" and to come back to the plant again, by producing sugary nectar and distinctive scents. The intriguing part is that plants are now using a psychoactive drug to influence the memorability of the plant. In Dr. Wright's experiments, the bees associated a reward with an odor, and as she refined her experiments, it became clearer that caffeine had a significant effect on memory.

Relevance to Class:

As we've studied in class, plants often go to great lengths to attract pollinators (in this case, bees), including fragrances, bright colors, and of course, the nectar itself. This is so that the pollinators who drink nectar from a flower move from plant to plant, they also spread the pollen, the male haploid gametophytes. These then fertilize the egg, and the plant can reproduce.

Source:

URL: http://www.nytimes.com/2013/03/08/science/plants-use-caffeine-to-lure-bees-scientists-find.html
Author: James Gorman
Date of Publication: 7 March 2013

Monocots Vs Dicots

Video Information:
         
           Title: Monocots vs Dicots Explained
           URL:  http://www.youtube.com/watch?v=gI2RxzAT-ww
           Youtube channel: http://www.youtube.com/user/robnelsonfilms

Summary of Video:

Monocots and dicots are two different types of angiosperms. Both plants share similar features, but these features are slightly different and determine whether the plant is a monocot or dicot.

Monocots usually have petals in multiple of three. Monocots have parallel veins. They have fibrous, spreading veins. Monocots have vascular bundles scattered all around the stem. Monocots seeds have one cotyledon in the seed.

Dicots have petals in multiples of 4 or 5. Dicots are net-veined. Taproots are dicot. Dicots have vascular bundles at the edge of the stem. Dicots have two cotyledons in the seed, or dicotyledons.

Relevance to Unit: 

This video shows five key, distinguishing characteristics between monocots and dicots. These two groups are mostly what make up angiosperms, which evolved most recently in evolutionary history. The distinct characteristics between these two groups show the different acquired traits between monocots and dicots, though these characteristics are homologous structures.

 

Peter Rakauskas's Blog Post

 

 

 

The Trapping Mechanism in Pitcher Plants

Wes Major

expertvillage

N.D.

http://www.ehow.com/video_4427854_the-trapping-mechanism-pitcher-plants.html

 

Summary of Video

The video is a neat description of how two different types of pitcher plants catch their prey.  They are much more passive than other carnivorous pants such as the Venus flytrap.  While the flytrap will close on its prey using its own power, the pitcher plant attracts prey with the smell of sweet nectar.  When the insect tries to land on the plant, it slips on a slippery substance and falls into the plant's pit of digestive enzymes, where it is ingested.  The next plant uses a similar trapping method, but it is made to capture flying insects who, when inside of the plant's hook-like chamber, believe that the white spots on the inside of the chamber are ways to get out, and will bash up against the side of the wall and knock themselves out, causing them to fall into the digestive enzymes of the plant.  

 

Relevance to Class

In class, we are learning about plants as our unit, but more specifically we are learning about what feeds a plant and how it gets these nutrients.  The swamps where the pitcher plant lives do not have the appropriate nutrients in their muddy soils, so the plants have taken to consuming other creatures, namely insects, to fulfill their nutritional needs. 

Similarities and Differences between Archaea and Bacteria

Relevance to class

In the beginning of term 3, we learned about archaea and bacteria in unit 8 (Microbes). In our class notes, we know that Bacteria is 1 of 3 domains. Archaea is another domain, just like bacteria. However, in the Biology textbook, there are many differences between archaea and bacteria. They are similar because both are prokaryotes. But their main differences are their cell structure, habitats, and genetic makeup. Bacteria Bacteria RNA polymerases are small/simple, while archaea have complex polymerases similar to eukaryotes. Introns are only in archaea, not bacteria. Bacterial cell walls are made of peptidoglycan, not found in archaea cell walls. These are the main differences between archaea and bacteria.

Summary: 

-Similarities between archaea and bacteria:
Archaea and bacteria have a few similarities in which they share. They are both prokaryotes, without any complex cell structure like eukaryotes. Archaea and bacteria have cell walls on the outside, providing structural support, and lets certain elements/substances pass through for cellular work. Bacteria is 1 of 3 domians, and Archaea is another domain. Both distinguish almost identical looks when looking through a microscope, since they are both prokaryotes. Bacteria and archaea both reproduce using binary fission, and move around using flagella.
-Differences between archaea and bacteria:
Archaea and bacteria have a lot of differences with each other. Becteria has cell wall made of peptidoglycan, whereas archaea don't. Both have different lipid composition. Archaeal lipids don't have any fatty acids, which are found in the other 2 domains (bacteria and eukarya). Archaea have side chains (polymers) made up of units of isoprene (chemical compound composed of C5H8). Archaea and bacteria similarly have 70S ribosomes, but archaea has a different shape. Archaea also has a complex RNA polymerases, bacteria has a more simple RNA polymerases. Archaea and bacteria are metabolically different from each other. Archaea dosn't use the process glycolysis  to break down glucose. Most types of archaea don't have Kreb's Cycle pathways, but few types do.

Source info:
URL: http://www.colorado.edu/eeb/EEBprojects/schmidtlab/studentres/EBIO3400/Lecture11.pdf
Publisher/creator: University of Colorado
Date visited: 3-7-13

Wasp Flowers

Wasp Flowers

Video Info:
Link: http://www.bbc.co.uk/nature/adaptations/Pollinator#p00lx7qx
Date of Publication/latest update: 2013
Publisher: BBC

Summary:
In the warmer parts of Europe there are certain orchids that have figured out a good way to spread their pollen. The orchids look very similar to female wasps. They have blue patches similar to the wings of female wasps as well as fur that is similar to the fur that covers a wasp's abdomen. They also produce the same identifying perfume that a female wasp makes. This draws in male wasps, and as the bee investigates the orchid, the flower's pollen carrier becomes attached to the bee's head. When the bee flies away and encounters another flower of the same species  some of that pollen rubs off onto the new flower. Through this process, the flowers are able to spread their pollen and become fertilized.

Significance:
In our current unit we are studying the structures of plants and their purposes. This video demonstrates the way the flower can manipulate animals into spreading their pollen by using the flower. We investigated the flower during our last lab as well as the video we watched in class.